Micrometric screw-cutting machine



' 15 graved cylin Patented Nov. 12, 192.9

MAURICE AUDIBERT, F VILLEURIBANNE, FRANCE MICROMETRIC SCREW-CUTTING MACHINE Application led November 29, 1927, Serial No. 236,454, and in France November 29, 1926.

The present invention relates to screw cuttin machines.

ne of the objects of the invention is to provide means for controlling, with micrometric precision, the movement of the elements cooperating to cut a thread.

Other objects will appear in the course of the detailed description now to be given with reference to the accompanying drawing in which the single figure illustrates, diagrammatically, one constructive embodiment of the invention.

' In some processes of color photography,

the photogra hic emulsion is spread on an enger and it is of the utmost importance that the spiral tracing on the cylinder be perfectly regular. The ordinary devices for producing these tracings are of the well-known type in which the means for rotating the cylinder coacts with the tool advancing mechanism. Any irregularity, play or defect in the `former is reflected by a corresponding irregularity in the functionin of the-latter. It appeared therefore, advisa le,

rst, to make the work rotating mechanism independent of the tool advancing mechanism and, second, to iind means for obtaining a strictly regular movement of each of said mechanisms. To insure a constant speed of rotation of the work it is only necessary to employ a synchronous motor fitted with appropriate rheostats and the like for adjusting the speed at any value desired.' The .control of the movement of the tool carriage is best effected by makin use of av gravitationally actuated device w ose action-is regulated by the fiow of liquid through a micrometrically calibrated orifice.

Referrin to the drawing, there is shown 40 a cylinder ,intended to be grooved,.mounted etween points and arranged to be rotated at any constant speed desired by synchronous motor M. Tool O is connected to a heavy piston P which descends by its own weight and displaces liquid L through a micrometri-l cally ca ibrated valve R.

chronous motor, the latter by the action of gravity. y

Having now particularly described and ascertained the nature of my said invention, and

in what manner the same is to be performed As will be evident from the foregoing description, rotation of the work is in of the translational movement of t e tool; 5 the former is maintained constant by the synendent l 

